There are a great variety of molded caps for closing various types of bottles, vials, and other containers. Many incorporate a hinged closure member for selectively enabling access to the contents of the container or preventing such access so that removal of the cap is not necessary. Dispensing bottles which contain liquid or semi-liquid materials require a closure which seals the liquid within the bottle to prevent leakage. The requirement for sealing necessitates tight interfitting members of the caps which, in turn, means that the closure members are difficult to open. Heretofore, attempts to open such caps have often resulted in broken fingernails, pinched fingers, and frustration. Caps for containers of non-liquid materials, such as pills and granulates have suffered from similar problems.
Liquid and semi-liquid materials, such as pharmaceuticals, condiments, cosmetics, and the like are often marketed in squeeze or squirt containers having spouts which pivot to close and seal the container. There are a number of existing spouted caps which are formed as two pieces, a separate spout which is pivoted within a cap body, the spout passage aligning with a passage in the cap when the spout is opened fully. Such designs are generally effective in sealing the contents when closed and are generally convenient to open and close. However, the need to manufacture and assemble two parts having tight enough tolerances to seal a liquid in the container results in a cap which is relatively expensive. Since most such containers and caps are not reusable and are normally discarded when the contents are exhausted, it is desirable for such caps to be as inexpensive as possible, commensurate with effective sealing and convenient operation.
One-piece spouted caps have been developed in which the spout is connected to the cap body by a flexible diaphragm and/or a bellows which allow the cap to seal when the spout is folded down into the body of the cap. The spout may be sealed at the outer end by a plug formation on a cylindrical wall of the cap body, by a seal boss at an inner end which is engaged by a portion of the diaphragm when the spout is folded closed, or by both. Because of the tightness of fit needed for an effective seal in the closed position, the caps of this type have been very difficult to open and to close.
Other types of caps, such as for squirt containers, containers for pills and granulates, and the like, may also be difficult to operate, particularly when tightness of fit for sealing the container is necessary.